Abstract
Thirty-four children, including nine relapsed cases with acute lymphoblastic leukemia (ALL) having hyperdiploidy (>50 chromosomes) were studied on clinical and cytogenetic characteristics. The majority of children initially with hyperdiploidy (>50 chromosomes), who showed favorable prognostic features such as lower leukocyte counts, lower serum lactic dehydrogenase levels, ages between 2 and 10 years, or the presence of common ALL antigen, had the most favorable outcome among childhood ALL (5-year survival rate was 100%). Even nine children, who showed poor prognostic features such as ages over 10 years, leukocyte counts over 2×104/mm3 or lymphomatous signs, had also the same favorable outcome. There were no differences in clinical features between 6 patients with additional chromosomal structural abnormalities and 19 patients without them. Duplication of the long arm of chromosome 1 was frequently observed as additional chromosomal structural abnormalities.
Patients with hyperdiploidy (>50 chromosomes) observed at relapse, who had the same favorable clinical features as those at diagnosis, had a poorer prognosis.
These findings show that initial hyperdiploidy (>50 chromosomes) is an independent favorable prognostic sign in childhood ALL and additional chromosomal structural abnormalities may not indicate a poor prognosis among childhood ALL with hyperdiploidy (>50 chromosomes). On the other hand, relapsed children with hyperdiploidy (>50 chromosomes) have not a favorable outcome after the onset of relapse.
